This Phase I project, a joint effort of Nimbus, Inc. and the Medical School of the University of California at Davis (UCD), has a long-term objective of bringing to clinical practice a system that can preserve donor hearts for up to 24 hours prior to transplantation. This length of preservation time compares to a 4-5 hour limit associated with current technology. Such a significant extension of time would be beneficial because better hostorgan matching would be possible, the number of donor organs available should increase, and the cost of retrieving and transporting hearts should effectively decrease. Through pioneering work by UCD investigators, a unique approach to biochemical nurturing and perfusion of donor hearts has been developed, and the validity of 24 hour cardiac preservation scientifically established. The University's basic research methodology will be applied by Nimbus to create a practical device. This Phase I effort has the following specific aims: complete design and fabrication of a system that provides environmental and perfusion conditions consistent with organ preservation methodology established by UCD research; and demonstrate system function through preservation of excised sheep hearts for 24 hours, verifying heart viability by determining specified indices and measurement of contractile activity. PROPOSED COMMERCIAL APPLICATION: The long-term goal is the creation of a portable preservation unit that would be marketed to all centers engaged in heart transplantation. The product itself would be comprised of an environmental cart and a set of disposables. Ultimately, its use would expand to preservation of other organs.